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GeoWorld March 2013

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within 3.7 percent of each other, and the lowest two bids were separated by just $14,000. Most importantly, the accepted bid was 20 percent lower than the engineer's estimate, saving the city and state $1.7 million. Drafting and design time also was greatly reduced. For example, a workflow was created that detailed more than 1,000 geometric and staking callouts on plan sheets. A Visual Basic Application was used to automatically assign proposed elevations to each detailed point and, after points were created, additional tools labeled the points by defined sets and automatically generated point tables for use in staking routines. Foth estimates that just this workflow reduced effort by 60 percent, saved 90 hours of manual drafting and cut 10 days from the project schedule, while reducing errors and greatly simplifying design changes. The use of specialized design modules, and aggregation into one model, was even more effective. "We saved about 120 hours of design and drafting time, compared to our previous methods," adds Buenger. "And that cut about 14 days from our project schedule." The bottom line is simple: final design was completed in the allotted six weeks, without cost overruns. A task that seemed "unachievable" was accomplished with minimal errors and high measurable quality. Safe and Sustainable The innovative nature of the actual project shouldn't be overlooked. Traffic studies suggest that, compared to traditional intersection design, the roundabout series will result in a 90-percent reduction of fatalities, a 76-percent reduction in injuries and a 35-percent reduction in all crashes. This improved safety is due mainly to slower vehicle speeds in roundabouts, fewer vehicle conflict points and, especially, fewer "severe" vehicle conflict points—in roundabouts, there are almost no opportunities for "T-bone" and head-on crashes. Rather, the crashes that take place are "better"—they're relatively safer sideswipes and rear-end collisions. In addition, pedestrian fatalities are reduced by a factor of eleven, and bicycle crashes are reduced, simply by reducing average intersection speeds. Even with the average intersection speed reduced, average corridor speed is increased by the elimination of signalized interchanges and routine stops. The elimination of signals, idling and stopping also works to reduce gasoline consumption and vehicle emissions, and it eliminates the cost of installing, powering and maintaining signal lights. Roundabouts even require less pavement. There are a lot of wins for DuPont and Johnston, and the trip to Carmel was well worth it. One advantage of 3-D design is that accurate renderings are easy to extract for use in meetings or proposals. A "visual task board" is an example of "lean processes" used on the NW 62nd Avenue project and helped organize brief, weekly meetings. Roadway redesign projects—even major ones such as this—aren't, in fact, special; they're ordinary and constantly take place all over the world. But each such project—and every infrastructure project—represents an opportunity to do something special. By applying the best technology to the best roadway design, Foth and DuPont made a positive contribution to life in Johnston, and the benefits of their work will reach across generations. Author's Note: This article was prepared with substantial assistance from Foth Senior Technology Manager Blaine Buenger who, in a long interview and in previously written documents, provided the facts, quotes and some specific phrasing. Angus W. Stocking is a licensed land surveyor who now writes fulltime on infrastructure topics; e-mail: angusstocking@gmail.com. M A R C H 2 O 1 3 / W W W . G E O P L A C E . C O M 21

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